1. Field of the Invention
This invention relates to ball joint assemblies useful at the inner end of the tie rod in a rack and pinion steering system for a vehicle.
2. Description of the Prior Art
It is known that rack and pinion steering systems employ ball joints between the rack and the tie rods in order to provide the necessary universal motion during wheel steering response. Examples of pertinent prior art include Wood U.S. Pat. No. 3,693,999 of Sept. 26, 1972; Adams U.S. Pat. No. 3,834,727 of Sept. 10, 1974; Bourdon U.S. Pat. No. 3,849,009 of Nov. 19, 1974; Wood U.S. Pat. No. 3,950,006 of Apr. 13, 1976; and Zukowski U.S. Pat. No. 4,187,033 of Feb. 5, 1980.
The problems with the foregoing prior art are numerous: such as full pre-loading of the ball joint before it is mounted on the rack which allows age hardening of the plastic material when allowed to have a long shelf life, and such as the expensive construction of the components having many parts which are difficult to assemble and obtain pre-load on a consistent basis before crimping the assembly before mounting on the rack.